Endocrine implications of bariatric surgery: a review on the intersection between incretins, bone, and sex hormones

• Published in: Physiological reports Vol. 7; no. 10; pp. e14111 - n/a
• Main Authors: Casimiro, Isabel, Sam, Susan, Brady, Matthew J.
• Format: Journal Article
• Language: English
• Published: United States John Wiley & Sons, Inc 01.05.2019; John Wiley and Sons Inc; Wiley
• Subjects: Adipokines - metabolism; Animals; Bariatric Surgery; Beta cells; Body weight loss; Bone and Bones - metabolism; Bone and Bones - physiopathology; Bone Density; Bone Remodeling; Bone surgery; Digestive system; Endocrinology and Metabolism; Female; Fertility; Gastrointestinal surgery; Gastrointestinal Tract; GLP‐1; Gonadal Steroid Hormones - metabolism; Hormones; Humans; Hypogonadism; incretins; Incretins - metabolism; Infertility; Insulin; Insulin Resistance; Invited Review; Invited Reviews; Male; Menopause; obesity; Obesity - metabolism; Obesity - physiopathology; Obesity - surgery; Pancreas; Physiology; Reproductive Conditions, Disorders and Treatments; Secretion; Sex hormones; Signal Transduction; Skeletal Muscle; Small intestine; Supplements; Treatment Outcome; Weight Loss; Womens health; incretins; GLP-1; obesity; Bariatric surgery
• ISSN: 2051-817X; 2051-817X
• DOI: 10.14814/phy2.14111

Bariatric surgery is now the most widely used intervention for the treatment of human obesity. A large body of literature has demonstrated its efficacy in sustained weight loss and improvement in its associated comorbidities. Here, we review the effect of bariatric surgery in gut hormone physiology, bone remodeling and the reproductive axis. Rapid improvements in insulin release and sensitivity appear to be weight loss independent and occur immediately after surgery. These effects on pancreatic beta cells are mostly due to increased gut hormone secretion due to augmented nutrient delivery to the small intestine. Bone remodeling is also affected by gut hormones. Phenotypic skeletal changes observed in mice deficient in GLP‐1 or GIP suggest that increased incretins may improve bone density. However, these positive effects may be counterbalanced by the association between weight loss and a reduction in bone density. Finally, studies have shown a marked improvement following bariatric surgery in infertility and PCOS in women and hypogonadism in men. Thus, the net effect on endocrine systems after bariatric surgery will likely vary on an individual basis and depend on factors such as comorbidities, peri‐menopausal state, amount of weight loss, and likelihood to adhere to vitamin supplementation after surgery. Gastric bypass surgery leads to dramatic weight loss and improvement in insulin resistance to the point of the resolution of type 2 diabetes in a majority of cases. These improvements in insulin sensitivity appear to be weight loss independent and occur immediately after bariatric surgery. The focus of the current review will be to summarize how the physiological changes that have been shown to arise from sustained weight loss after bariatric surgery affect other interrelated endocrine processes such as bone remodeling and improve obesity‐related hypogonadal dysfunction.